Here is one quick article about how to disable editor display in comment with drupal.When you install any module for editor like ckeditor or WYSIWYG editor, which replace textarea fields with the CKEditor.
And It replaces all textarea fields with CKEditor like comment section too.So if you don’t want editor for comment section, you need to follow below steps.
1.Login to the drupal Admin panel.
2. Go to the Structure >> Content Types. You will see below screen and in this Go to edit of article.
3. Select Comment Fields from top menu and you will get below screen. In this screen, select edit of Label comment.
4. Here, Select “Plain Text” in Text Processing.
That’s it.open your frontend and check the comment section.